

 struct ListNode 
 {
    int val;
    ListNode *next;
    ListNode() : val(0), next(nullptr) {}
    ListNode(int x) : val(x), next(nullptr) {}
    ListNode(int x, ListNode *next) : val(x), next(next) {}
};

class Solution 
{
public:
    ListNode* removeNodes(ListNode* head)
    {
        if (head == nullptr)
            return nullptr;
        head->next = removeNodes(head->next);
        if (head->next != nullptr && head->val < head->next->val)
            return head->next;
        else
            return head;
    }
};
